The present invention relates to a digital information recording medium having a limited storage amount and premised on variable bit rate recording.
The present invention also relates to a digital information recording/playback system using a digital information recording medium having a limited storage amount.
Furthermore, the present invention relates to a digital video recorder for recording and playing back information such as digital moving pictures and the like, which are compressed by MPEG.
In recent years, systems for playing back the contents of optical discs that record video data (moving pictures), audio data, and the like have been developed, and have prevailed for the purpose of playing back movie software titles, karaoke data, and the like as in LDs (laser discs), video CDs (video compact discs), and the like.
DVD (digital versatile disc) standards that use MPEG2 (moving picture expert group) international standards, and also use an audio compression scheme such as AC-3 (digital audio compression), or the like, have been proposed. The DVD standards include read-only DVD video (or DVD-ROM), write-once DVD-R, recordable/readable DVD-RW (or DVD-RAM).
The DVD video (DVD-ROM) standards support MPEG2 as a moving picture compression scheme, and AC-3 audio and MPEG audio in addition to linear PCM as audio recording schemes in accordance with the MPEG2 system layer. Furthermore, the DVD video standards are configured by adding sub-picture data obtained by runlength-compressing bitmap data for superimposed dialogs, and presentation control data (navigation data) for fastforward, rewind, data search, and the like. The standards also support the UDF Bridge format (a hybrid of UDF and ISO9660) to allow computers to read data.
An optical disc currently used in DVD video (DVD-ROM) is a single-sided, single-layered 12-cm disc having a storage amount around 4.7 GB (gigabytes). A single-sided, two-layered disc has a storage amount around 9.5 GB, and a double-sided, two-layered disc is capable of recording a large amount of data around 18 GB (when a laser of a wavelength of 650 nm is used for reading).
An optical disc currently used in DVD-RW (DVD-RAM) is a 12-cm disc, and has a storage amount of 2.6 GB (gigabytes) on one surface, i.e., 5.2 GB on the two surfaces. The currently available DVD-RAM optical disc has a smaller storage amount than that of a DVD-ROM disc of the corresponding size. However, technical developments for expanding the amount of the DVD-RAM disc have been extensively made, and it is certain that a DVD-RAM disc having a storage amount more than 4.7 GB on one surface will be available in the near future.
However, since an MPEG2 video file that can obtain high picture quality has a large data size, the currently available DVD-RAM disc (single-sided 2.6 GB disc or double-sided 5.2 GB disc) does not always have a sufficient recordable time (around 1 hour for 2.6 GB disc, around 2 hours for 5.2 GB disc).
That is, the storage amounts of individual DVD-RAM discs do not have an enough margin for the purpose of long-time moving picture recording in the status quo, and efficient data management (release of unnecessary storage areas, management of variable recording rates in correspondence with the remaining recordable amount and/or monitoring of the remaining recordable time at a variable recording rate, and the like) is required. Even if the storage amount of a DVD-RAM disc increases in the future, requirements for longer-time recording arise accordingly, and efficient data management is also required.
In an optical disc such as a DVD-RAM on which data can be written or rewritten, a function of allowing the user to easily edit data is demanded. However, no recording/playback apparatus which can be easily handled by the user for home use is available to date.
It is an object of the present invention to provide a variable bit rate digital information recording/playback system, which can extend the recordable time for a digital recording medium having a limited storage amount.
It is another object of the present invention to provide a digital information recording/playback system, which can inform or display the remaining recordable time upon executing digital recording on a digital recording medium having a limited storage amount at a variable bit rate.
It is still another object of the present invention to provide a digital recording medium which can compression-record digital moving picture information at a variable bit rate, and can record dummy data that is used for editing recorded information after recording.
It is still another object of the present invention to provide a remote controller which makes a system, which performs digital information recording at a variable bit rate on a digital recording medium having a limited storage amount, inform or display the recording bit rate and/or the remaining recordable time at that bit rate.
It is still another object of the present invention to provide a computer program or a method corresponding to the processing contents of this program, which is used for achieving the above objects using a computer system such as a personal computer or an information processing terminal comprising a microcomputer.
It is still another object of the present invention to provide a recording method, recording apparatus, or recording medium, which allows user""s easy edit operation to attain flexible edit operations.
It is still another object of the present invention to provide a recording method, recording apparatus, or recording medium, which can efficiently manage data and, consequently, can flexibly manage keep units.
It is still another object of the present invention to provide a recording method, recording apparatus, or recording medium, which can efficiently manage data by assigning erase or delete prohibition flags in units of cells.
In order to achieve the above objects, a digital information recording/playback system according to an embodiment of the present invention informs or displays the average recording rate used currently and/or the remaining recordable time upon executing digital recording at a variable recording rate on a digital recording medium having a limited storage amount.
Also, a digital information recording/playback system according to an embodiment of the present invention adjusts the recording quality and recordable time for a digital recording medium by changing the variable recording rate.
Furthermore, a digital information recording/playback system according to an embodiment of the present invention changes the average recording rate upon recording a program of a predetermined duration in correspondence with the remaining amount of a recording medium so as to record the entire program.
Moreover, a digital information recording/playback system according to an embodiment of the present invention changes the average recording rate upon recording unrecorded programs in correspondence with the remaining amount of a recording medium, the number of unrecorded programs, and the recording times required by these programs, so as to record all the predetermined number of programs.
A digital recording medium according to an embodiment of the present invention records digital moving picture information in a predetermined unit at a variable rate, and also records dummy information that can be used for editing recorded information in a unit corresponding to the predetermined unit.
A remote controller according to an embodiment of the present invention has an operation key for making a system, which performs digital information recording on a digital recording medium having a limited storage amount at a variable bit rate, inform or display the average recording rate used currently and/or the remaining recordable time.
A computer readable program or a processing method corresponding to this program according to an embodiment of the present invention includes: a process for, when a free space or area that remains on a medium having a limited storage amount becomes smaller than a predetermined value as a result of information recording on the medium at a variable recording rate, calculating the remaining recordable time on the medium on the basis of the free space and variable recording rate; and a process for displaying the variable recording rate and the remaining recordable time at that variable recording rate on the basis of the result of the remaining recordable time calculation process.
A computer readable program or a processing method corresponding to this program according to an embodiment of the present invention includes: a process for, when a recordable free space remains on a medium which has a limited storage amount and undergoes information recording at a variable recording rate, calculating an average recording rate for the medium on the basis of the free space and a length of information to be recorded on the medium; and a process for setting the calculated average recording rate as a recording rate for the free space.
A computer readable program or a processing method corresponding to this program according to an embodiment of the present invention includes: a process for, when a free space that remains on a medium having a limited storage amount becomes short upon information recording on the medium for a predetermined period of time at a variable recording rate, decreasing an average recording rate for the medium discontinuously or stepwise on the basis of the free space and an information recording time; and a process for setting the decreased average recording rate as a recording rate for the free space.
A computer readable program or a processing method corresponding to this program according to an embodiment of the present invention includes: a first average recording rate calculation process for calculating an average recording rate for a medium having a limited storage amount on the basis of a remaining amount on the medium and the information recording time upon information recording on the medium for a predetermined period of time; a second average recording rate calculation process for, when the calculated average recording rate is smaller than a predetermined lower limit value, changing recording contents of the information, and then calculating an average recording rate for the medium on the basis of the changed information recording time and the remaining amount on the medium; and a process for, when the average recording rate calculated by the first or second average recording rate calculation process is not less than the predetermined lower limit value, setting the calculated average recording rage as a recording rate of the recording contents of the information for the remaining amount.
A computer readable program or a processing method corresponding to this program according to an embodiment of the present invention includes: a process for, when a remaining amount of a medium having a limited storage amount is not less than a predetermined value upon digital moving picture recording on the medium at a variable recording rate, performing the digital moving picture recording by MPEG2; and a process for, when the remaining amount of the medium is smaller than the predetermined value upon digital moving picture recording on the medium at a variable recording rate, performing the digital moving picture recording by MPEG1.
A computer readable program or a processing method corresponding to this program according to an embodiment of the present invention includes: a process for, when a remaining recordable amount on a medium having a limited storage amount is not less than a predetermined value, recording dummy information together with predetermined information to be recorded; and a process for, when the remaining recordable amount on the medium is smaller than the predetermined value, canceling recording of the dummy information.
In an embodiment of the present invention, means for setting an erase prohibition range indicates the erase prohibition range of a file. When this range is not set in units of cells of the current cell, the current cell is divided by a cell separator to set an advanced cell sequence. A reassemble means reassembles presentation management information of the advanced cells and current cell, and appends erase prohibition information to the presentation management information of the advanced cells that belong to the set range.
With the above arrangement, playback information can be subjected to flexible playback sequence management, and user""s operations are easy.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.